Organic material stabilized with alpha,alpha,alpha&#39;,alpha&#39;-tetrakis(4-hydroxy-3,5 - disubstituted phenyl)xylene and process thereof

ABSTRACT

ORGANIC MATERIAL NORMALLY TENDING TO UNDERGO OXIDATIVE DETERIORATION STABILIZED WITH A TETRAPHENOLIC COMPOUND OF THE FOLLOWING FORMULA IS DISCLOSED;   (3-R1,4-(HO-),5-R2-PHENYL)2-CH-R5-CH-((3-R3,5-R4-1,4-   PHENYLENE)-OH)2   WHEREIN R1, R2, R3, AND R4 ARE ALKYL OR ARALKYL, AND R5 IS 0-, M- OR P-PHENYLENE.

United States Patent ORGANIC MATERIAL STABILIZED WITH ALPHA,

ALPHA,ALPHA',ALPHA'-TETRAKIS(4-HYDROXY- 3,5 DISUBSTITUTED PHENYL)XYLENEAND PROCESS THEREOF Gordon D. Brindell, Crystal Lake, and Joseph P.Wuskell,

Barrington, Ill., assignors to The Quaker Oats Company, Chicago, Ill. NoDrawing. Filed May 12, 1972, Ser. No. 252,860

Int. Cl. C08f 45/58 US. Cl. 260-4585 S 24 Claims ABSTRACT OF THEDISCLOSURE Organic material normally tending to undergo oxidativedeterioration stabilized with a tetraphenolic compound of the followingformula is disclosed;

R1 1 l R; ram-@cn-m-cnQ-on R] i I 2 wherein R R R and R are alkyl oraralkyl, and R is 0-, mor p-phenylene.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to organic materials stabilized with a new class ofantioxidants.

Description of the prior art Tetra-2,5-disubstituted phenolicderivatives of phthalaldehyde having the following formula are known asantioxidants:

(Formula I) wherein R is o-, mor p phenylene and X and Y are alkylgroups.

We have unexpectedly found that the tetra-2,6-disubstituted phenolicderivatives are superior antioxidants.

SUMMARY OF THE INVENTION (Formula II) wherein R R R and R areindependently selected from the group consisting of alkyl and aralkyl;and R is o-, m-, or p-phenylene.

The present invention may further be described as a process forstabilizing organic material which comprises incorporating with saidorganic material from 0.01 perice cent to 10 percent by weight of acomposition of Formula II.

By alkyl in Formula II we mean methyl, ethyl, propyl, butyl, pentyl,hexyl, heptyl, etc and where the alkyl group contains three or morecarbon atoms may be straight or branched chain. We prefer that the alkylgroup contains from one to 10 carbon atoms. Preferred alkyl groupsinclude for example, methyl, ethyl, isopropyl, isobutyl, sec-butyl,tert-butyl, l-methylbutyl,tert-pentyl, 2- methyl'butyl, neopentyl, 1methylpentyl, 1,1 dimethylpentyl, 1 ethylpentyl, 1,1-diethylpentyl,Z-methylpentyl, 2,2 dimethylpentyl, 2-ethylpentyl, 2,2-diethylpentyl, 1-methylhexyl, 1,1 dimethylhexyl, l-ethylhexyl, 2-methy1- hexyl,2,2-dimethylhexyl, Z-ethylhexyl, etc.

The aralkyl in Formula II may be benzyl, styryl, or substituted aralkylsuch as chlorobenzyl, bromobenzyl, iodobenzyl, fluorobenzyl,methoxybenzyl, ethoxybenzyl, methylbenzyl, ethylbenzyl, ortert-butylbenzyl. We prefer that the aralkyl group contains less than 20carbon atoms. Where the alkylene portion of the aralkyl group containstwo or more carbons, the alkylene group may be straight or branchedchain. We prefer that the aralkyl group is substituted with a groupwhich is halo, alkoxy, or alkyl. Any substitution is on the aryl portionof the aralkyl group and may be made for one or all of the availablehydrogens. Suitable alkoxy and alkyl groups include chloro, bromo, iodo,and fluoro. Suitable alkoxy and alkyl groups include those containingfrom one to 13 carbon atoms.

Exemplary tetra-2,6-disubstituted phenolic derivatives of phthalaldehydeuseful in our invention include the following:

a,ot,a',u'-tetrakis 4-hydroxy-3 ,5 -dimethylph'enyl )-xylene a,ot,a,od-tetrakis (4-hydroxy-3 ,5 -diethylphenyl) -xylene Ot,0t, u',a-tetrakis(4-hydroxy-3 5 -dipropylphenyl) -xy1ene;

a,u,a,'a'-tetrakis(4-hydroxy-3,S-dibutylphenyl) -xylene;

a, a,a',a-tetrakis (4-hydroxy-3,5-dipentylphenyl -xylene;

a,a, u',ot'-tetrakis (4-hydroxy-3 ,5 -dihexylphenyl -xylene;

a,oc,oc',a't6trakiS (4-hydroxy-3 S-diisopropylphenyl) xylene;

a,a,ot,a'-tetrakis(4-hydroxy-3 ,5 -diisobutylphenyl) -xylene;

a,oc,a',a'-tetrakls (4-hydroxy-3,S-di-sec-butylphenyl) xylene;

a,a,a,'u-tetrakis (4-hydroxy-3 ,5 -di-tert-butylphenyl) xylene;

a,a,a',a'-t6il'aki5 [4-hydroxy-3,5-di( I-methylbutyl) phenyl] -xylene;

a,a,a',a'-tetrakis (4-hydroxy-3 ,5 -di-tert-pentylphenyl) xylene;

a,m,u',a'-tetrakis [4-hydroxy-3,5-di (Z-methylbutyl) phenyl] xylene;

u,a,a',a-tetrakis (4-hydroxy-3,S-dineopentylphenyl) xylene;

a,a,ot',a-tetrakis [4-hydroxy-3,5-di( l-methylpentyl) phenyl] xylene;

u,a,u',a'-tetrakis [4-hydroxy-3 ,5 -di- 1,1-dimethylpentyl)phenyl]xylene;

a, a,a,a'-tetrakis [4-hydroxy-3 ,5 -di( l-ethylpentyl phenyl] xylene;

a,a,a,a'-tetrakis [4-hydroxy-3 ,5 -di( 1,1-diethylpentyl) phenyl]xylene;

a,a,u,a'-tetrakis[4-hydroxy-3,5-di(2-methylpentyl) pentyl] -xylene;

a,a,a',a'-tetrakis [4-hydroxy-3,5-di(2,2-dimethylpentyl) phenyl] xylene;

oz, a,a',a-tetrakis 4-hydroxy-3,5-di (Z-ethylpentyl phenyl] xylene;

a, a,a',ot'-tetrakis [4-hydroxy-3,5-di- (2,2-diethylpentyl)phenyl]xylene;

0t,0t,0t',0t'-tetIaklS [4-hydroxy-3,5-di l-methylhexyl) phenyl] -xylenea,a,a',a'-tetrakis- [4-hydroxy-3,5-di( 1-ethylhexyl)phenyl] xylene;

a,a,m',a'-tetfakls[ 4-hydroxy-3 ,5 -di-( 1,1-diethylhexyl) phenyl]xylene;

a,a,a', x-tetrakis [4-hydroxy-3 ,5 -di (2,2-dimethylhexyl phenyl]xylene;

a,a,a,a'-tetrakis [4-hydroxy-3,5-di Z-ethylhexyl phenyl xylene;

u x x', a'-tetrakis [4-hydroxy-3,5-di- (2,2-diethylhexyl) phenylxylene;

a,c,a',a'-tetrakis (4-hydroxy-3 ,5 -dibenzylphenyl xylene;

a,oc,oc',oc'-tetrakiS [4-hydroxy-3 ,5 -di p-chlorobenzyl) phenyl]xylene;

a,u,a',a'-tetlakis [4-hydroxy-3 ,S-di p-bromobenzyl) phenyl] xylene;

u,a,a',a-tetrakis [4-hydroxy-3,5-di (p-iodobenzyl phenyl] xylene;

u,ct,0t,'a'-t6t1'akiS [4-hydroxy-3 ,S-di nonylbenzyl phenyl] xylene;

a,a,a',et'-tetrakis [4-hydroxy-3,5-di (p-methoxybenzyl) phenyl] xylene;

a,a,a',a'-tetrakis(4-hydroxy-3-tert-butyl-S-methylphenyl) xylene;

a,a,a',a'-tetrakis 4hydroxy-3,5-distyrylphenyl xylene;

a,a,u',u'-tetrakis [4-hydroxy-3 ,5 -di p-methylbenzyl) phenyl] xylene;

and a,a,u',a'-tetrakis- [4-hydroxy-3,5-di (o-chlorob enzyl) phenyl]xylene.

Suitable phenols for use in preparing the tetraphenolic compoundsinclude those of the formula:

(Formula III) wherein R and R are consistent with R R R and R, asdefined above. All of the suitable phenols are commer- :ially availableor prepared by known techniques.

The reaction is preferably carried out in an inert solvent, for examplean alcohol such as methanol, ethanol, Z-propanol, ethylene glycol,ethylene glycol monoethyl :ther, etc. Ethanol is the preferred solventsince it allows solubility of the reactants and, in many cases,crystallizaion of the product directly from solution. The reaction isnost conveniently carried out at the reflux tempertaure )f the solventfor 0.5 to about 24 hours. We prefer the reaction temperature to beabout 60 C. to about 65 C. [n those cases where the product does notprecipitate on :ooling, it may be readily isolated by removal of thesolvent or by dilution with water. Liquid products may be isolated inthis manner.

The reaction is preferably carried out in the presence 3f an acidcatalyst. Acidic catalysts include organic acids, norganic acids, andFriedel-Crafts catalysts. Suitable organic acids for example are thephosphoric and sulfonic iCidS such as phosphoric acid, pyrophosphoricacid, ethalesulfonic acid, benzenesulfonic acid, toluenesulfonic acid,and naphthalenesulfonic acid. Suitable inorganic icids include themineral acids such as sulfuricacid and iydrochloric acid. Friedel-Craftscatalysts including aluninum chloride, boron trifluoride, ferricchloride, zinc :hloride, and the like, may also be employed.

The catalysts are employed in a catalytic amount which iepends on thereactants and reaction conditions. For :xample, the amount may rangefrom about 2 to 500 parts )f catalyst per 100 parts by weight of thephenol. Pre- :'erred concentrations of the catalyst are about 80 toabout [50 parts on the same basis.

The tetraphenolic compounds described above are useful as antioxidantfor organic materials normally tending to undergo oxidativedeterioration. By oragnic material normally tending to undergo oxidativedeterioration, we mean to include material based in whole or in part ona skeleton comprising interconnected carbon atoms which upon exposure tooxygen or air loses its desirable properties and becomes weak, brittle,cracked, discolored, viscous or the like. Exemplary organic materialsare polymers, hydrocarbon liquids, particularly gasoline and lubricatingor fuel oils, hydrocarbon solids or semi-solids, such as waxes, greasesand the like; elastomers, such as natural and synthetic rubber; andfeeds or foodstuffs.

Typical polymers include polyolefins, polyurethanes, polyethers, andpolyamides. Suitable include for example polystyrene, polyvinylchloride, polyvinyledene chloride, polyvinyl fluoride, polyvinylbutyral, polymethyl acrylate, ethylene vinyl acetate and copolymers, andethylene propylene terpolymers. Suitable polyethers include for examplepolyformaldehyde and polytetramethylene ether glycol.

Hydrocarbon liquids stabilized by the above described tetraphenolicderivatives include motor lubricating oils, gear and transmission fluidsbased on hydrocarbon oils, and the like. Fuel oils, such as furnace oilsand light kerosene fractions, including gas turbine fuels, are alsostabilized by our compositions.

Solid or semi-solid hydrocarbons, such as wax and grease, and alsoimproved by incorporation therein of the tetraphenolic compounds used inthis invention.

Such solid polymeric elastomers as natural and synthetic rubber arestabilized against hardening, cracking, and checking with thetetraphenolic derivatives described. Exemplary of natural rubbers isHevea brasiliensis, while synthetic rubbers includepolystyrene-butadiene rubber; polybutadiene; polyisoprene; polyneoprene;polybutyl rubber; polynitrile-butadiene rubbers, polystyrene-chloroprenerubbers; polyacrylate-butadiene rubbers; and polyurethane rubber.

The tetraphenolic derivatives of this invention are also useful toenhance the stability of the natural fats and oils. For example, thefollowing edible oils can be stabilized with our compositions:shortening, lard, butter, coconut oil, cotton seed oil, soybean oil,palm oil, corn oil, peanut oil, sunflower seed oil, safilower oil, oliveoil, and the like or mixtures thereof. These oils may have been treated,as by hydrogenation, interesterification, or fractional crystallization,to modify their melting points.

In general the tetra-2,6-disubstituted phenolic derivatives should beused with the organic material to be stabilized in an amount effectiveand sutficient to stabilize the material. The requisite amount will, ofcourse, depend both on the efficiency of the particular tetraphenolicderivative and on the nature of the normally oxidizable substrate inwhich it is employed. It has been our experience that from 0.01 percentto 10 percent by weight based on the weight of the organic material issufficient. Amounts down to as little as 0.0001 percent by weight may beeffective in some cases.

It is to be understood that the stabilizing effect of the tetraphenoliccompounds is considerably enhanced by conventional synergists such ascertain sulfides and polysulfides. The synergist is used in conventionalamounts. For example an amount of synergist from about 0.1 p rcent toabout 1 percent by weight of the organic material to be stabilized issatisfactory but we prefer to use from 0.1 percent to 0.5 percent byweight.

As sulfides there may be mentioned dialkylsulfides, particularly whereinthe alkyl groups are long chain such as dodecyl groups since the lowerdialkylsulfides are too volatile to be effective,di(substituted)alkylsulfides particularly esters of bis-carboxyalkylsulfides such as dilauryl, distearyl, ditridecyl, or dioctadecylthiodipropionates or thiodibutayrates, dibenzylsulfide such asbis(Z-hydroxy-S- methy1benzyl)sulfide and bis(3 tert-butyl-Z-hydroxy-S-methoxybenzyl)sulfide, diaryl sulfide, sulfides such as yields from thephenols noted and were found to have diphenyl sulfide, dicresyl sulfide,2,2'-dihydroxy-5,5-dithe properties reported in Table I.

TABLE I Composition (percent by weight) Test Calculated Found No. PhenolProduct tetraphenolic derivative C H C H 1 2,6-dimethylphenol. a, a, a,a-tetral is(4-hydroxy-3,5-dimethylphenyl) p-xyiene.. 254-259 81.9 7.281.8 7.4 2 2,6-dnsobutylphenoL.a,a,a',a-tetrak1s(4-hydroxy-3,fi-dnsobutylphenyl) p-xylene.. 149-15183.2 9.8 83.5 9.9

methyl diphenylsulfide, diphenyldisulfide, dialkyldithio- EXAMPLE 3phosphates such as bis(diisopropyldithiophosphoryl)di- Again using themethod f Example 1, the f ll i S111fi'de, and y p y phenols.tetraphenolic derivatives were prepared in excellent yields d filfurtthel' l f g a l? the olgaflltc g i t from the phenols noted and werefound to have the meltin a 1 1011 0 con almng a s a izmg amoun o e ramgpomts reported m Table TABLE II Test No. Phenol Product tetraphenoliederivative M.P. C.)

3 2-tert-butyl-fi-methylphenol a,a,a a-tetralds(thydroxy-3-tert-buty1-5-methy1phenyl)p-xylene. 219-221.2,6-dnsopropylphenol.-- 11,11,111,a'-tetrak1s(4-hydrxy-3,5-diisopropylphenyl)p-xylene 172-177.2,6-di-see-butylphenol. a,a,a',a'-tetrakls(4-hydroxy-3,5-d-sec-buty1phenyl)p-xylene...- 159-162. 2,6-dr-2-ethy1hexy1phena,a,a,a'-tetralns[4-hydroxy-3,5-d1(2-ethylhexyl) henyllp-xylene Oil at27 C 2,6-drhenzylphenol 11,11,a,a-tetrakis(4-hydr0xy-3,S-dibenzylphenylp-xylene 179-184. 2,6-d -4-methylbenzy1pheno1- a,a,a,a-tetraks(4-hydroxy-3,5-di-4-methylbeuzylphenyl)p-xylene.. 183-188.2,5-d1methy1phenol a,a,a a'-tetraks(4-hydroxy-3,6-d1methy1phenyl)p-xylene 324-330. 102-tert-buty1-5-methylphenol. a,a,a,ol-tetrakis(4-hydr0xy-3-tert-butyHi-methylphenyl)p-xylene... 308-316.

phenolic compound and a synergist may contain such EXAMPLE 4 gh g s i zz is s i antloxldants colormg agents A number of candidate antioxidantswere evaluated in r g g cis-polyisoprene. The results of these tests areset forth DESCRIPTICN OF THE PREFERRED in Table III. Cis-polyisoprenewas cut up into small pieces EMBODIMENTS 30 and dissolved overnight in arapidly stirred solution of 500 ml. of toluene. If the antioxidant wasreadily soluble in toluene, 0.100 g. was then added to thecis-polyisoprenetoluene solution and stirred until it dissolved. If theantioxidant was not readily soluble in toluene it was dissolved in asmall amount of an appropriate solvent and then added to the toluenesolution. A sample of the solution was taken up in a capillary dropperand 15 drops were placed on a circular sodium chloride plate, 1 inch inThe following embodiments of this invention are shown for the purpose ofillustrating the invention and demonstrating the best mode forpracticing the invention. It will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit and scope of the invention as it is moreprecisely defined in the subjoined claims.

EXAMPLE 1 diameter. The plate was then put in a 130 C. oven for In a 500ml. 3-neck flask equipped with a stirrer, cona few minutes to evaporatethe toluene. denser, nitrogen inlet, and a thermometer, ml. of Aninfrared spectrum was run of the film on the plate. methanol and 20 ml.of concentrated sulfuric acid were The plate was then put back in theoven. Every hour it admixed and cooled to 15 C. Then 6.7 g. ofterephthalalwas removed and another infrared spectrum was run.

dehyde, 42 g. of 2,6-di-tert-butyl phenol, and 50 ml. of This procedurewas repeated until appreciable oxidation methanol were combined in abeaker and immediately 45 had taken place as indicated by the appearanceof a carad-ded to the stirred mixture in the flask. The reactionmixbonyl band at 1700-1750 cmf The test was ended when ture was thenheld at C. under a nitrogen atmosphere the carbonyl band exceeded 6 cm.on a Perkin Elmer for 5 hours. The reaction mixture was then cooled toroom Infrared Spectophotometer, Model 710. This length is aptemperature(27 C.) and allowed to stand overnight. proximately equal to the lengthof the peak at 1450 cmr The product was separated from the reactionmixture by filtration, was triturated with ethanol, washed with waterEXAMPLE 5 until the water washes were neutral, and dried in an oven 65at A number of candidate stabilizers were incorporated in The productwas identified as oc,oz,ot',or.'-tetlakiS(4-hy- 5 mil thick samples of pyp py d h resultdroxy-3,S-di-tert-butylphenyl)p-xylene. Analysis of theing materials evaluated y heat aging the films- In some d t ff d d th fll i d My, between 272 of the tests where indicateddilaurylthiodipropionate was C. and 281 C., and analyzing to C, 83.1percent; H, 10.0 added as Synergistpercent. C H O requires C, 83.2percent; H, 9.8 percent. In the hea g g P lyp p film samples 5 EXAMPLE 2mil in thickness were maintained in an oven at 140 C.

Each sample was tested for loss of structural integrity.

Using the method of Example 1, the following tetra- The number of hoursshown in the table are the total phenolic derivatives were readilyprepared in excellent elapsed hours before the film cracked orembrittled when flexed. The film was embrittled when it crumbled to awherein R R R and R are independently selected powder. from the groupconsisting of alkyl and aralkyl; and R is The resulting data arepresented In Table IV. 0-, m-, or p-phenylene.

TABLE IV Percent by Oven hours weight Percent by Test tetraphenolicweight Em- No. Compound derivative synergist; Cracked brittled Blank O l27 ,a,a,a'-tetrakis(4-hydroxy-3,5dirnethylpheny1)p-xylene 0.1 0 31 31a,a,a,a-tetrakis(4-hydroxy-3,5-dimethylpheuyl)p-xylene plusdilaurylthiodipropionate. 0.1 0.8 602 644 26 a,a-tetrakis(4-hydroxy-3,fi-dimethylphenyl)p-Xylene 0.1 0 30 30 27a,a,a',a-tetrakis(4-hydroxy-3,G-dimethylphenyl)p-xylene plusdilaurylthiodipropionate.. 0. 1 0.3 500 507 EXAMPLE 6 2. The compositionof claim 1 wherein a dialkylsulfide The solubility of some of thetetraphenolic derivatives 15 is present as a synergist.

prepared above in ethanol and toluene at 27 C. is reported in Table V.

3. The composition of claim 2 wherein the dialkylsul- TAB LE VSolubility (g./l00 ml.)

Test No Compound Ethanol Toluene 28 a,a,a ,a-tetrakis(4-hydroxy-3,S-dimethylphenyl) p xylene 3 17 29..1:,11,a,a-tetrakisE4-hydroxy-3,6dimetl1ylphenyl)p-xylene 14 17 30a,a,a',a tctrakiS 4-hydroxy-3-tert-butyl-S-methylphenyl)p-xylene. 9 9 31a,a,a,a-tetrakis(4-11ydr0xy-3-tert-butyl-6-methylphenyl) p'xylene. 9 l

The above examples clearly demonstrate the accomplishment of thisinvention. Example 1 demonstrates our best mode for preparing the noveltetraphenolic derivatives of our invention.

Examples 2 and 3 further demonstrate the best mode of practicing ourinvention. Tests 1-8 inclusive are embodiments of our invention. Tests9-l0 inclusive are not embodiments of our invention but were preparedfor the purposes of comparison with our compositions in these and in thefollowing examples. A comparison of the melting point given in Test 1with Test 9 and a comparison of that in Test 3 with Test 10 shows thatthe tetra-2,6-disubstituted phenolic derivatives of our invention havelower melting points than the 2,5-derivatives.

In Example 4 a comparison of Tests 12 and 14 With Tests 13 and 15respectively clearly demonstrates that our tetra-2,6-disubstitutedphenolic derivatives are unexpectedly superior to the 2,5-derivatives asantioxidants in cis-polyisoprene. Tests 16-22 inclusive further indicatethe effectiveness of our compositions as antioxidants incispolyisoprene.

In Example 5, a comparison of Test 24 with Test 26 and more particularlyof Test with Test 27 shows the unexpected superiority of ourtetra-2,6-disubstituted phenolic derivatives over the prior art2,5-derivatives. The superiority of our compositions as stabilizers forpolypropylene is most evident when used in conjunction with a synergist.

Example 6 demonstrates by comparing Test 28 with Test 29 and Test 30with 31 that our tetra-2,6-disubstituted phenolic derivatives have thesame or greater solubility than the 2,5-derivatives in typical alcoholand hydrocarbon solvents. This facilitates easier distribution inorganic material to be stabilized.

From the foregoing descriptions we consider it to be clear that thepresent invention contributes a substantial benefit to the antioxidantart by providing a new and use ful antioxidant suitable for stabilizingorganic materials normally tending to undergo oxidative deterioration.

We claim:

1. Organic material selected from the group consisting of naturalrubber, synthetic rubber, polyethylene, polypropylene andethylene-propylene terpolymer, which organic material normally tends toundergo oxidative deterioration in the presence of air or oxygen,containing an effective amount of a composition having the formula:

fide is dilaurylthiodipropionate or distearylthiodipropionate.

4. The composition of claim 2 wherein R in the formula is p-phenylene.

5. The composition of claim 2 wherein the composition of the formula ispresent in an amount from 0.01 percent to 10 percent by weight based onthe weight of the organic material.

6. The composition of claim 2 wherein the composition of the formula ispresent in an amount from 0.01 percent to 10 percent by weight based onthe weight of the organic material, and R in the composition isp-phenylene.

7. The composition of claim 6 wherein the alkyl group of the compositioncontains from 1 to 10 carbon atoms and the aralkyl group contains lessthan 20 carbon atoms.

8. The composition of claim 7 wherein the alkyl group of the compositionselected from the group consisting of methyl, ethyl, isopropyl,sec-butyl, isobutyl, tert-butyl, and 2-ethylhexyl; and the aralkyl groupis selected from the group consisting of benzyl, 4-methoxybenzyl,2-chlorobenzyl, and 4-methylbenzyl.

9. The composition of claim 8 wherein the composition of the formula isa,a, x',a'-tetrakis(4-hydroxy-3,5-dimethylphenyl p-xylene.

10. The composition of claim 8 wherein the composition of the formula isu,u,a',a-tetrakis(4-hydroxy-3,5-diisopropylphenyl p-xylene.

11. The composition of claim 8 wherein the composition of the formula isu,a,a',a-tetrakis[4-hydroxy-3,5-di- (3-methyl-5-tert-butylphenyl1p-xylene.

12. The composition of claim 8 wherein the composition of the formula isa,a,a',a-tetrakis(4-hydroxy-3,5-diisobutylphenyl)p-xylene.

13. The composition of claim 8 wherein the composi tion of the formulais a,a,a,a-tetrakis(4-hydroxy-3,5-disec-butylphenyl p-xylene.

14. The composition of claim 8 wherein the composition of the formula isa,a,u,ot-tetrakis(4-hydroxy-3,5-ditert-butylphenyl p-xylene.

15. The composition of claim 8 wherein the composition of the formula isa,a,a',a-tetrakis[4-hydroxy-3,5-di- 2-ethylhexyl phenyl] p-xylene.

16. The composition of claim 8 wherein the composition of the formula isu,a,u,a-tetrakis(4-hyclroxy-3,5- di-benzylphenyl p-xylene.

17. The composition of claim 8 wherein the composition of the formula isa,a,a,a-tetrakis[4-hydroxy-3,5 di p-methoxybenzyl phenyl p-xylene.

18. The composition of claim 8- wherein the composition of the formulais a, x,tz',a'-tetrakis[4-hydroxy-3,5- di(p-methylbenzyl)pheny1]p-xylene.

19. The composition of claim 8 wherein the composi- References Citedtion of the formula iS a,u,ot',ot'-tetrakis[4-hydl'0Xy-3,5-di- Po-chlorobenzyl) phenyl p-xylene.

20. The composition of claim 2 wherein the organic 3,309,337 3/1967Hurlock at R material to be stabilized is natural rubber. 3,422,0591/1969 Taylor et 26045-95 R 21. The composition of claim 2 wherein theorganic 2,816,945 12/1957 Baver et 260810 material to be stabilized issynthetic rubber.

22. The composition of claim 1 wherein the material MAURICE WELSH PnmaryExammer Payethylene' us. 01. X.R.

23. The composition of claim 1 wherein the material 10 is polypropylene.4478; 99183; 25248.2, 404; 260-4595 R, 398.5,

24. The composition of claim 1 wherein the material 8 0, 814 is anethylene-propylene terpolymer.

